CDK9 and CHARGE syndrome: Although only the two variants [c.280C>T, p.(R94C) and c.673C>T, p.(R225C)] have been registered for CDK9 in the Human Gene Mutation Database to date (Professional version 2020.2, accessed September 23, 2020) [11] and reported to be associated with the intellectual disability with normal visual and hearing [12] and the CHARGE syndrome [4], respectively, the variants detected in this study were novel and have not been reported previously.